Exam 19: Life in the Universe: Are We Alone

In addition to asteroids, impacts also provided the primitive Earth with water and organics.

From the beginnings of life on Earth, it took less than a billion years for single- celled organisms to evolve to multicellular organisms.

Thanks to the far- flung Voyager and Pioneers, knowledge of our presence has now spread out over 30 light-years.

Living cells have already been recreated in our laboratories.

What is SETI? How is it being done?

Why might the Cassini- Huygens probe to Titan be considered disappointing to exobiologists?

Each factor in the Drake Equation has a well- known, established value.

If we are optimistic in our assumptions about the development of life and intelligence, then the number of technological civilizations currently in the galaxy should equal the

Europa is one of the most promising of the bodies in the outer solar system for life in its salty seas.

Approximately how long between the evolution of single versus multicellular organisms?

Our earliest atmosphere, formed by outgassing, was much poorer in than now.

The Drake Equation seeks to estimate the number of technological civilizations in the galaxy.

Of the terrestrial planets, Mars seems most promising to exobiologists.

In addition to the proper chemistry, it is that determines the feasibility of life on a given planet.

The Murchison meteorite, a carbonaceous chondrite, contained many of the amino acids needed by living things on Earth.

Comets were likely a major agent in bringing both water and organic molecules to the surface of the early Earth.

Why is Earth a stronger radio emitter than the Sun?

In the Miller- Urey experiment, the electric discharge was meant to simulate

Organic molecules are

Most SETI searches are done at